My issued U.S. Pat. No. 4,955,393, discloses certain improvements in mouthguards. The invention which is the subject of this application relates to a method for making the mouthguard that is described in U.S. Pat. No. 4,955,393, and to other mouthguards of the type in which a relatively more rigid main body having at least one trough for a dental arch contains a relatively less rigid liner material in the trough.
In addition to the features that have already been disclosed in the mouthguard that is the subject of U.S. Pat. No. 4,955,393, I have discovered that unexpected beneficial results can be obtained in a mouthguard by fabricating the mouthguard in a particular way. Specifically, I have found that by making the trough liner of the same, but lower durometer material as the main body material, it is possible to join the liner and main body together by bonding without the use of separate adhesive or other means of mechanical joining, and that the resulting mouthguard will exhibit a surprising improvement in impact absorption when in use. This attribute has been demonstrated by comparative testing with mouthguards of other, different constructions.
I have further discovered that principles of my invention can be practiced with certain liner materials and certain main body materials other than materials which are identical except for durometer. This endows the inventive principles with a generic character that is not limited to the particular materials involved. According to this generic character, the liner and the main body materials are ones which will directly bond together without the use of separate adhesive or other means of mechanical attachment when the liner material is molded directly onto the main body material, and the liner material is one which is tooth-impressionable after it has been directly molded onto the main body.
While the prior art has recognized the disadvantage of using separate adhesive or other means of mechanically attaching a mouthguard liner to a mouthguard body (see Wolicki U.S. Pat. No. 3,457,916), the advantage of directly joining the liner to the main body by allowing liner material to cure onto the main body (see Wolicki U.S. Pat. No. 3,457,916 and Ross U.S. Pat. No. 2,833,278), and the desirability of having a main body which is tooth-impressionable after the molding thereof (see Greenberg U.S. Pat.No. 3,505,995), no one has heretofore conceived of a method for making a mouthguard in which a liner material is molded directly onto a relatively more rigid main body for bonding thereto without the use of separate adhesive or other means of mechanical attachment and in which the liner thus formed is both relatively less rigid than the main body and also tooth-impressionable after it has been so bonded to the main body.
The various aspects of my invention will be described in greater detail in the ensuing description which is accompanied by drawings and presents a presently preferred embodiment of the invention in accordance with the best mode contemplated at this time in carrying out the invention.